SEQUENCE OF A MENKES-TYPE CU-TRANSPORTING ATPASE FROM RAT C6 GLIOMA-CELLS - COMPARISON OF THE RAT PROTEIN WITH OTHER MAMMALIAN CU-TRANSPORTING ATPASES

Rat Atp7a occupied a single open reading frame (27-4502) which coded f or a protein of 1492 residues. Rat Atp7a was 98% and 95% identical to published sequences for the mouse and Chinese hamster, respectively, a nd 94% homologous to human ATP7A. Compared to ATP7A, the rat transcrip t coded for an additional alanine (A446) in the heavy metal binding (H mb) domain and showed a 34 bp gap in the 3'UTR. Based on published seq uence data, hydropathic profiles for rat, mouse, Chinese hamster, and human Cu-ATPases were practically identical with the exception of 8 ad ditional amino acid residues between the 4th and 5th Hmb sites in the human. As deduced from amino acid sequence data, Hmb was predicted to have regions with helical and beta structures. All four species had fi ve of the six metal binding sites centered within hydrophobic regions. The comparative analyses suggested that the Hmb region of the molecul e could experience numerous amino acid substitutions with no apparent disruption to the ATPase transport function whereas variations to the ATPase domain would be more critical.